7K FORCES

What is a force?

What unit is force measured in?

What do we use to measure forces?

Forces

Go round the stations.

Write at least two sentences for each station.

FORCE STATIONS

What is the unit of weight?

How can you measure weight?

What is the unit of mass?

How can you measure mass?

How do I change weight to mass on earth?

Weight and mass

Aim: To investigate the relationship between weight and mass.

Object Mass (g) Weight (N)

Number of pieces

Mass (g) Weight (N)

Now, change mass to kgObject Mass (g) Weight (N) Mass (kg)

Graph

Level 3 When the mass is bigger the weight…Level 4 Number examples

e.g. when the mass is 10g the weight is 0.1NLevel 5 Why does this happen? Can you describe the pattern using a formula?

Weight = …. Are there any results that do not fit the pattern?

Conclusion

Running on the moonhttp://youtu.be/CyOt6RUs9mE

Jumping on the moonhttp://youtu.be/HKdwcLytloU

What force always acts downward on an object (on earth)?

What force pushes up on an object in water?

Floating or sinking

Aim: To investigate which is the best material to make a float?

How do you calculate density?

What is the unit of density?

What is density?

Density

Aim: To investigate which is the best material to make a float.

Why?

What is the same and different about the cubes?1. Brass

2. Copper3. Aluminium4. Iron5. Zinc6. Tin7. Lead8. Polythene9. Hard wood10. Soft wood11. Cork12. Acrylic

Remember cm3 is the same as mlL

H

D

VOLUME = L X H X D

FINISH YOUR RESULTS TABLE

DENSITY = MASS(G) / VOLUME (CM3)(/CM3)

Use these key words to explain what you have found out about floating and sinking.

upthrust weight force

float sink buoyancy density

Less dense denser

Which material would you use to make a float?Give 3 reasons why.

Conclusion

Does density change if there is a bigger or smaller piece of the material?

How does salininty of water affect whether an object floats or sinks?

Density 2

7 layer density column demo

Aim: To find out how the number of weights a scuba diver needs changes with where they swim.

The water will represent: The Mediterranean, The Baltic sea, The Dead Sea, The Black Sea and a Lake

Write a prediction with the word BECAUSE Write down the independent, dependent

and control variables

You put weights in water with different salinity and measure the weight.

What are the two types of force?

Name some forces.

Types of force

Separate the cards into two groups

FrictionAir resistanceWater resistance

MagnetismStatic electricityGravity

What happens if forces are balanced?

What happens if forces are unbalanced?

Balanced and unbalanced forces

One where the forces acting are the SAME (balanced)

One where the forces are DIFFERENT sizes (unbalanced)

Separate the cards into two groups

Balanced Unbalanced

Change shape

Go faster (accelerate)

RWC 2011 highlights http://youtu.be/Cq6lcH7NKAw

Tackles http://youtu.be/aD_1sone-Mk

Line outs http://youtu.be/OCQfggoUSNU

VIDEOS

What is friction?

What is friction in air called?

What is friction in water called?

Friction

Can you feel the friction?

Rub your hands together

Friction and energy

When friction occurs heat energy is produced

Kinetic energy Heat energy

Friction Friction is a force which opposes the motion

of 2 objects It makes it harder for things to slide Friction can occur between solids, and for

anything moving through a liquid or gas

What examples of friction can you think of?

FRICTION STATIONS

http://youtu.be/jSu0Tvlm6LY http://youtu.be/QMW_uYWwHWQ?t=2m17s

Mythbusters phone books

This hotel is built on sand

Friction 2 When is friction useful?

When is friction not useful?

How can friction be reduced?

Put the cards in order from most to least friction

When do we want to reduce friction?

E.g. A bicycleFill in this table naming the parts of a bike where friction is wanted or not wanted.

Friction is wanted

Friction is not wanted

- Gripping onto handlebars

- In the axle where the wheel turns round

Tyre

Handlebar

Seat

Axle

PedalChain

Gears

Wheel

Brakes

How can friction be reduced?

Slick sliding soap practical

You will be sliding soap down a slope, you will investigate how to make it slide further.

Aim: Prediction: Variables: Independent, dependent, control

Results- Homework Plot a bar chart

Conclusion◦ Describe the results:

With nothing the soap went ____cmWith oil the soap went ____cm.With water the soap went ____cm.

◦ Which had most friction?

◦ Which had least friction?

Results- Homework Plot a bar chart

Conclusion◦ Describe the results:

With nothing the soap went ____cmWith oil the soap went ____cm.With water the soap went ____cm.

◦ Which had most friction?

◦ Which had least friction?

◦ Why?

◦ How does this relate to real situations

What happens to a spring when you add masses to it?

When is this useful for us?

Springs

Aim: To investigate why elastic is used in bungee cords.

Success criteria:

Draw a scientific diagram of the experiment

Design a results table

Results

Graph

What are the units for speed?

How do you calculate speed?

Speed

You will be investigating how one factor affects friction (not liquids)

This practical will be assessed for AF3, AF4 and AF5

Assessed practical